It is well known in the subterranean well drilling and completion art that relatively fine particulate materials may be produced during the production of hydrocarbons from a well that traverses an unconsolidated or loosely consolidated formation. Numerous problems may occur as a result of the production of such particulates. For example, the particulates cause abrasive wear to components within the well, such as tubing, pumps and valves. In addition, the particulates may partially or fully clog the well creating the need for an expensive workover. Also, if the particulate matter is produced to the surface, it must be removed from the hydrocarbon fluids using surface processing equipment.
One method for preventing the production of such particulate material to the surface is gravel packing the well adjacent the unconsolidated or loosely consolidated production interval. In a typical gravel pack completion, a sand control screen is lowered into the wellbore on a work string to a position proximate the desired production interval. A fluid slurry including a liquid carrier and a relatively coarse particulate material, such as sand, gravel or proppants, which is typically sized and graded and which is referred to herein as gravel, is then pumped down the work string and into the well annulus formed between the sand control screen and the perforated well casing or open hole production zone.
The liquid carrier either flows into the formation or returns to the surface by flowing through a wash pipe or both. In either case, the gravel is deposited around the sand control screen to form the gravel pack, which is highly permeable to the flow of hydrocarbon fluids but blocks the flow of the fine particulate materials carried in the hydrocarbon fluids. As such, gravel packs can successfully prevent the problems associated with the production of these particulate materials from the formation.
It has been found, however, that a complete gravel pack of the desired production interval is difficult to achieve. For example, incomplete packs may result from the premature dehydration of the fluid slurry due to excessive loss of the liquid carrier into highly permeable portions of the production interval causing the gravel to form sand bridges in the annulus. Thereafter, the sand bridges may prevent the slurry from flowing to the remainder of the annulus which, in turn, prevents the placement of sufficient gravel in the remainder of the annulus.
Numerous attempts have been made to improve the quality of the gravel packs. For example, changing fluid slurry parameters including flow rate, viscosity and gravel concentration and providing alternate paths for the fluid slurry delivery provide for a more complete gravel pack in some completion scenarios. Even using these improved techniques, however, a nonuniform distribution of the gravel that results in the presence of localized spaces that are void of gravel within the production interval is typically undetectable. As such, well operators are typically not aware that corrective action is required until after sand production from the well has commenced.
Accordingly, a need has arisen for a system and method for gravel packing a production interval traversed by a wellbore that provide for monitoring downhole conditions during a gravel packing operation. A need has also arisen for such a system and method that generate a real time profile of the downhole conditions surrounding the sand control screen. A need has further arisen for such a system and method that inform well operators that corrective action is required during both the completion and production phases of well operation.